Synthesis, processing, and thermoelectric properties of bulk nanostructured bismuth telluride (Bi₂Te₃)

Abstract

Bismuth telluride (Bi 2 Te 3 ) is the best-known commercially used thermoelectric material in the bulk form for cooling and power generation applications at ambient temperature. However, its dimensionless figure-of-merit-ZT around 1 limits the large-scale industrial applications. Recent studies indicate that nanostructuring can enhance ZT while keeping the material form of bulk by employing an advanced synthetic process accompanied with novel consolidation techniques. Here, we report on bulk nanostructured (NS) undoped Bi 2 Te 3 prepared via a promising chemical synthetic route. Spark plasma sintering has been employed for compaction and sintering of Bi 2 Te 3 nanopowders, resulting in very high densification (>97%) while preserving the nanostructure. The average grain size of the final compacts was obtained as 90 AE 5 nm as calculated from electron micrographs. Evaluation of transport properties showed enhanced Seebeck coefficient (À120 mV K À1 ) and electrical conductivity compared to the literature state-of-the-art (30% enhanced power factor), especially in the low temperature range. An improved ZT for NS bulk undoped Bi 2 Te 3 is achieved with a peak value of $1.1 at 340 K.

Vapor–solid synthesis and enhanced thermoelectric properties of non-planar bismuth selenide nanoplates on graphene substrate

“…For TI and thermoelectric applications, it is preferable to explore Bi 2 Se 3 nanostructures. Their extremely large surfaceto-volume ratio reveals the TI surface effect which in bulk materials can be masked by bulk transport [10,11], while morphological modulation and size control was found to have immense potential to reduce thermal conductivity through enhancing phonon boundary scattering and tuning other important for thermoelectrics parameters as the electrical conductivity and Seebeck coefficient [12][13][14].…”

Fabrication and characterization of nanostructured thermoelectric FexCo1-xSb3

“…The experimental procedure is divided into three major steps, as detailed in our earlier work [5,[19][20][21]. First a thermodynamic modeling has been performed to determine the chemical synthesis conditions.…”

“…Following this a thermochemical process of no more than 3 to 4 hours of heating will result in high purity skutterudites [5,[19][20][21]. In this work, iron has been selected as the substituent element and the materials have been synthesized via a novel chemical synthesis technique.…”

“…In this work, iron has been selected as the substituent element and the materials have been synthesized via a novel chemical synthesis technique. Skutterudites nanopowders with several concentrations of iron (20,25 and 30% of Co sites) have been fabricated. Structural and thermoelectric transport properties of the fabricated materials are thoroughly investigated.…”

Microstructure tailoring in nanostructured thermoelectric materials

“…Most TE oxide nanopowders can be obtained via this method, such as CaMnO 3 18 ) can be also prepared via the co-precipitation method. Saleemi et al 19 prepared Bi 2 Te 3 powders by reduced co-precipitation method and then bulk samples were consolidated using SPS, respectively. Compared to the conventional solid state synthesis, co-precipitation process, combined with SPS, can restrain the grain growth so that nanoceramics bulk can be obtained with improved TE properties.…”